package com.xingchen.netty.websocket;

import com.xingchen.netty.global.ChannelSupervise;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http.websocketx.*;
import io.netty.util.CharsetUtil;
import org.apache.log4j.Logger;
import com.xingchen.netty.auth.AdminAuth;
import com.xingchen.netty.auth.UserAuth;
import com.xingchen.netty.config.Config;
import com.xingchen.netty.domain.UserInfo;
import com.xingchen.netty.utils.UrlUtils;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.Date;
import static io.netty.handler.codec.http.HttpUtil.isKeepAlive;

public class NioWebSocketHandler extends SimpleChannelInboundHandler<Object> {

    private AdminAuth adminAuth =new AdminAuth();
    private UserAuth userAuth =new UserAuth ();
    private final Logger logger=Logger.getLogger(this.getClass());

    private WebSocketServerHandshaker handshaker;

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        logger.debug("收到消息："+msg);
        if (msg instanceof FullHttpRequest){
            //以http请求形式接入，但是走的是websocket
                handleHttpRequest(ctx, (FullHttpRequest) msg);
        }else if (msg instanceof  WebSocketFrame){
            //处理websocket客户端的消息
            handlerWebSocketFrame(ctx, (WebSocketFrame) msg);
        }
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        //添加连接
        logger.debug("客户端加入连接："+ctx.channel());
        ChannelSupervise.addChannel(ctx.channel());
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        //断开连接
        logger.debug("客户端断开连接："+ctx.channel());
        ChannelSupervise.removeChannel(ctx.channel());
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }
    private void handlerWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame){
        // 判断是否关闭链路的指令
        if (frame instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());
            return;
        }
        // 判断是否ping消息
        if (frame instanceof PingWebSocketFrame) {
            ctx.channel().write(
                    new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        // 本例程仅支持文本消息，不支持二进制消息
        if (!(frame instanceof TextWebSocketFrame)) {
            logger.debug("本例程仅支持文本消息，不支持二进制消息");
            throw new UnsupportedOperationException(String.format(
                    "%s frame types not supported", frame.getClass().getName()));
        }
        // 返回应答消息
        String request = ((TextWebSocketFrame) frame).text();
        logger.debug("服务端收到：" + request);
        TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString()
                + ctx.channel().id() + "：" + request);
        // 群发
        ChannelSupervise.send2All(tws);
        // 返回【谁发的发给谁】
        // ctx.channel().writeAndFlush(tws);
    }
    /**
     * 唯一的一次http请求，用于创建websocket
     * */
    private void handleHttpRequest(ChannelHandlerContext ctx,FullHttpRequest req) throws UnsupportedEncodingException {
        String method =req.getMethod().toString();
        String token= UrlUtils.getParam(req.getUri(), Config.TOKEN);
        // 服务器推送消息通过post链接
        //要求Upgrade为websocket，过滤掉Post
        if(method.equals("POST")){
            logger.debug("服务端收到POST 推送消息鉴权在这里，目前只支持uri里传参：uri参数msg需要通过encodeURIComponent(msg)加密" + req);
            String urlmsg = UrlUtils.getParam(req.getUri(),Config.MSG);
            String  msg= URLDecoder.decode(urlmsg,"UTF-8");
           if(msg==null){
               return;
           }
            String type= UrlUtils.getParam(req.getUri(),Config.TYPE);
//        验证后台推送消息授权，这个权限最好设置ip白名单，只限制内部服务器调用
            if(adminAuth.getAdminInfo(token)!=null){
                TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString() + ctx.channel().id() + "：" + msg);
                if(type.equals("all")){
                    // 群发
                    ChannelSupervise.send2All(tws);
                }else {
//                    单发
                    String cid= UrlUtils.getParam(req.getUri(),Config.CHANNELId);
                    if(null !=cid ){
                        Channel channel= ChannelSupervise.findChannel(cid);
                        if(channel!=null){
//                            单发消息
                            channel.writeAndFlush(tws);
                        }
                    }
//                    或者直接单发消息
//                    ChannelSupervise.send(cid,tws);
                }
            }
        }
        if (!req.decoderResult().isSuccess()  || (!"websocket".equals(req.headers().get("Upgrade")))) {
            //若不是websocket方式，则创建BAD_REQUEST的req，返回给客户端
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
            return;
        }
//客户端建立websocket链接在这里
        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory("ws://localhost:8081/websocket", null, false);
//        websocket验证登录授权
        UserInfo userInfo =userAuth.getUserInfo(token);
        if(userInfo!=null){
            handshaker = wsFactory.newHandshaker(req);
            if (handshaker == null) {
                WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
            } else {
                req.setUri("uid="+userInfo.getUid());
                handshaker.handshake(ctx.channel(), req);
            }

        } else {
            WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
        }
    }
    /**
     * 拒绝不合法的请求，并返回错误信息
     * */
    private static void sendHttpResponse(ChannelHandlerContext ctx,
                                         FullHttpRequest req, DefaultFullHttpResponse res) {
        // 返回应答给客户端
        if (res.status().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(res.status().toString(),CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
        }
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        // 如果是非Keep-Alive，关闭连接
        if (!isKeepAlive(req) || res.status().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
}
